82 STUDIES IN TASMANIAN MAMMALS, LIVING AND EXTINCT, 



The female of N. mitchelli (Owen's cast, and type 

 skull of Zygomaburus), while exceeding all the measure- 

 ments of .V. tasmanicum, falls short of those of the assum- 

 ed male in about the same proportions as usually exist be- 

 tween male and female skulls. Not having the actual skull 

 to work upon, we omit various details, but the cast and 

 a series of photographs, supplied by the Curator of the 

 Australian Museum, are available to us, and a careful 

 study of these leads us to formulate the above statement. 

 As a single note, expressing the rate of reduction, we may 

 cite the widths of the nasal platforms. In the male, the 

 measurement is 175 mm., but in the female this suffers 

 diminution to 150 mm. A glance at the outlines of the 

 implantation surfaces available in the male and female 

 skulls, as given in our figure, will also show that if a 

 horn existed in the female (as apparently it did) it ad- 

 vanced more upon the nasal aperture than that of the 

 male did. In other words, the tips of the nasals were 

 carried nearly across the narial aperture, and the an- 

 terior surface of the horn touched the tips of the nasals. 

 This gives an outline for the base of the horn that makes 

 a distinct departure from that obtaining in the male. 

 Such differences in modern Rhinoceroses might also be 

 cited, and where the horn is long, slender, and pointed 

 forward, the females use it to direct the young, the latter 

 being always in advance of the mother when on the march. 

 As long as the female skull of Notoiherium mitchelli alone 

 remained available for study, the existence of a, horn 

 would only have been suggested as a possibility, but the 

 male skull from Smithton carries it forward to the cogency 

 of a proof. Again, Nototherium tasmanicum, viewed as 

 an isolated factor, that manifested an elaborately under- 

 propped nasal platform, too weak to carry an effective 

 fighting weapon, and no excess of cervical power, sug- 

 gested nothing more than the "fighting bosses" — postu- 

 lated by Professor Watson — and accordingly it was only 

 with the acquisition of the male skull of Notoiherium 

 mitchelli that the stirpian homologies determined their 

 full significance. Professor Watson's suggestion is, to- 

 day, so obviously close to the truth, that it is practically 

 a demonstration of actual fact, and we herewith record 

 cur thanks for the strong sidelight thus thrown upon an 

 cbscui'e paheontological point. 



It will now be necessary, in order to deal with the 

 question of sex among the Nototheria, to show that the 

 type skull of Zygomaturus (and Owen's cast) is the female 

 of N, mitchelli, and not the sex variant of Nototherium 

 tasmanicum, nor is that latter the sex variant of the skull 



